Given below are two statements:
Statement I: | \({d\vec l}\) of a current-carrying wire carrying a current, \(I\) is given by: \({d\vec B}=\dfrac{\mu_0}{4\pi}~I\left({d\vec l}\times\dfrac{\vec r}{r^3}\right ),\) where \(\vec{r}\) is the position vector of the field point with respect to the wire segment. |
The magnetic field due to a segment
Statement II: | The magnetic field of a current-carrying wire is never parallel to the wire. |
1. | Statement I and Statement II are True and Statement I is the correct explanation of Statement II. |
2. | Statement I and Statement II are True and Statement I is not the correct explanation of Statement II. |
3. | Statement I is True, and Statement II is False. |
4. | Statement I is False, and Statement II is True. |
A wire carrying a current \(I_0\) oriented along the vector \(\big(3\hat{i}+4\hat{j}\big)\) experiences a force per unit length of \(\big(4F\hat{i}-3F\hat{j}-F\hat{k}\big).\) The magnetic field \(\vec{ B}\) equals:
1. \(\dfrac{F}{I_0}\left(\hat{i}+\hat{j}\right)\)
2. \(\dfrac{5F}{I_0}\left(\hat{i}+\hat{j}+\hat{k}\right)\)
3. \(\dfrac{F}{I_0}\left(\hat{i}+\hat{j}+\hat{k}\right)\)
4. \(\dfrac{5F}{I_0}\hat{k}\)
1. | case (I) but not in case (II). |
2. | case (II) but not in case (I). |
3. | both cases (I) and (II). |
4. | neither of cases (I) and (II). |
1. | a force along \(+y\) axis only. |
2. | a force along \(-y\) axis. |
3. | zero force, but a torque. |
4. | no force and no torque. |
Assertion (A): | Work done by magnetic force on a charged particle moving in a uniform magnetic field is zero. |
Reason (R): | Path of a charged particle in a uniform magnetic field, projected in the direction of field, will be a straight line. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
1. | \( \dfrac{\mu_{0} i}{2 \pi a}(\hat{i}+\hat{j})\) | 2. | \( \dfrac{\mu_{0} i}{2 \pi a}(-\hat{i}+\hat{j})\) |
3. | \(\dfrac{\mu_{0} i}{2 \pi a}(-\hat{i}-\hat{j})\) | 4. | \(\dfrac{\mu_{0} i}{2 \pi a}(\hat{i}-\hat{j})\) |
Which of the following statements about a moving coil galvanometer is incorrect?
1. | The spring in a galvanometer provides a counter torque that balances the magnetic torque. |
2. | A galvanometer has multiple turns of wire to enhance the torque acting on the coil. |
3. | In all positions, the magnetic field \(B\) remains parallel to the plane of the coil. |
4. | The deflection \(\phi\) indicated by the scale is proportional to the square of the current flowing through the coil. |